One third of Arctic ice cap now missing; Midwestern floods; tropical update

Sea ice in the Arctic continues its record decline, thanks to unusually cloud-free conditions and above-average temperatures. For August 21, the National Snow and Ice Data Center estimated that fully one third of the Arctic ice cap was missing, compared to the average levels observed on that date from 1979-2000. Sea ice extent was 4.92 million square kilometers on August 21, and the 1979-2000 average for the date was about 7.3 million square kilometers. Arctic sea ice has fallen below the record low absolute minimum of 4.92 million square kilometers set in 2005 by about 8%, with another 3-5 weeks of the melting season still remaining. Reliable records of sea ice coverage go back to 1979.

Figure 1. Extent of the polar sea ice on August 21, compared to the average for the date from the 1979-2000 period (pink line). Image credit: National Snow and Ice Data Center.

With one third of the Arctic ice cap already gone, and another month of melting to go, we need to consider what effect this will have on weather, climate, and sea level rise. Well, we don't need to worry about sea level rise, since the polar sea ice is already in the ocean, and won't appreciably change sea level when it melts. However, the remarkable melting of the ice cap will likely lead to unusual weather patterns this fall and winter. The lack of sea ice will put much more heat and moisture into the polar atmosphere, affecting the path of the jet stream and the resultant storm tracks. Expect a much-delayed arrival of winter to the Northern Hemisphere again this year, which may lead to further accelerated melting of the ice cap in future years.

Last week, I remarked that the most recent images from the North Pole webcam show plenty of melt water and rainy conditions near the Pole. It turns out that was misleading, since the webcam is on a ship that was headed towards the pole, but had not reached it. There have been rainy conditions at the Pole this summer, and there is some open water there, but this is not uncommon in summer. Shifting ice frequently opens up leads (cracks) with open sea water at the Pole. It was one of these open leads that British swimmer Lewis Gordon Pugh swam in for 18 minutes this July to draw attention to global climate change.

Midwest floodingTo get an idea of the magnitude of the flooding that has hit the Midwestern U.S. during the past ten days, take a look at the total amount of rain from August 10-22 (Figure 2). We can blame Tropical Storm Erin for the rain in Texas and Oklahoma (up to 11 inches), and for the nine flooding deaths that occurred in those states. However, the unbelievable rain amounts in excess of 20 inches in Minnesota and Wisconsin were primarily due to a frontal system--with the help of some copious moisture pumped northwards by the counter-clockwise circulation around Erin while it spun over Oklahoma.

Tropical updateThere are no threat areas in the Atlantic to discuss. Two of our four reliable forecast models, the NOGAPS and ECMWF, are predicting that a tropical depression could form off the coast of Nicaragua on Sunday. The models forecast that this system would move inland over Nicaragua and Honduras by Monday.

"Posted By: MichaelSTL at 9:58 PM GMT on August 24, 2007. the Dust Bowl was also a regional event that affected only the United States, not the globe""Posted By: DallasGumby at 10:25 PM GMT on August 24, 2007. Texas almost certainly faces a future of perpetual drought," according to a group of scientists at Columbia University. (emphasis mine.)"

Exactly the point.

And it's these same types of local anomalies that have been used as examples of "global" warming.

Michael, in the 60's-70's scientists and climatologists were predicting the coming of a new ice age, based on that same data. The fact that the sea ice was expanding.

There are records - sealing, whaling, fishing - including archaeological - that go back a lot further.

They could not record "catch" records and get their ships in there if it was frozen over. ;-)

Ahhhh, the Dust Bowl! On April 7 of this year, the Dallas Morning News devoted most of its front page to an extensive article proclaiming that "Texas almost certainly faces a future of perpetual drought," according to a group of scientists at Columbia University. (emphasis mine.) "Drought conditions are expected to resemble the Dust Bowl years of the 1930s and Texas' worst-ever drought of the 1950s, Dr. Seager said. Unlike those droughts, however, the new conditions won't be temporary, the study found," proclaimed the article.

The article, and the release of the report, was timed to coincide with the Intergovernmental Panel on Climate Change's latest report.

Almost immediately, it started raining all over Texas. Here in North Texas, it rained all May. June in this area was, I believe, the second wettest June in recorded history, with 350 times the normal June rainfall. July, a month in which it typically rains two to three days, saw 18 days of recorded precipitation. To date, we are almost double our normal year-to-date rainfall.

Now, I'm the first to criticize those who use anecdotal information to prove a scientific argument or use a set of information too small to prove or disprove their point (such as using 28 years of arctic icesheet data to prove abnormality of this year's icesheet). But, it is pretty funny to have our local so-called "mainstream" newssource trumpet perpetual drought, accompanied by a large picture of parched, cracked soil; only to have mother nature respond by opening the spigots to the point where the local weather personalities are openly questioning whether we should start collecting two of each species to assemble on our ark!

StormW I have been pretty busy today with work, and have not had much chance to monitor buoy readings in GOM today. However, on first glance this evening there appears to have been a pretty significant drop in pressures across the E. GOM. Have you noticed this by chance, and could that be a sign of that ULL working its' way down to the surface?

My only question about the ice melts is, that is a substancial amount of FRESH water into a salt water body of water you would think that that would be throwing off the salinity of the water even if it was only by very small percentages, wouldn't you expect this to start killing of fish, or other types of sea life????

Problem with South Florida is that the building code was relaxed in the 70's thru the 80's. A lot of wood frame houses were built (my current one included) and it really wasn't until after Hurricane Andrew that the codes were tightened down. . . .The current 2005 building code is very strict and in fact houses built in the 70's and 80's couldn't be economically "retro-fitted" or fixed to meet current codes. . . . BTW, my previous house which was built in 1949 went thru Andrew without a hitch. Even the interior walls were solid conrete or poured CBS block. I bet the island homes are built like this too and that is why there wasn't as much damage. The design and construction practices of these homes has been around for over 50 years! Just look at any home in the old (east) section of Hialeah with the flat concrete roofs. After you replace the jalousie (spelled that way on purpose) windows with impact windows they are not going anywhere...

Well said, Dakster! My folks built in the late sixties; ALL the walls are concrete block (this is still the standard building practice in most houses today). Even with the jalousies, lots of those old houses make it better because they used to have fairly decent hurricane shutters as well. Quite a few of the older houses in Hollywood are built similarly. This is when developers (1) had a clue what to expect from tropical weather and (2) had more of an eye towards quality and less of one towards the almighty $$$.

IMHO, sheet rock is not appropriate for home design in hurricane prone areas.

Welcome back psychic amy! Will I win the lottery in two months? Please enlighten me on how you can predict that nothing will form next week into friday. You dont know if a disturbance will form or not.

"For instance, we don't have any records to indicate the amount of melt that took place during the 1930s, a period that we do know was warmer than what we see now."

That would be the great dust bowl of the 30's to 40's.

They started taking data on the size of the sea ice, right after the peak of the 70's hysteria predicting the new ice age. A prediction based on the "fact" that the sea ice was expanding.So unless it continued to expand and we are now in a new ice age, it had no where else to go but down.

How can we talk about a "remarkable" ice melt and also state that reliable sea ice records only go back to 1979? Seems to me this could be another example of an "answer" ("global warming") looking for a question.

With less than 30 years of reliable data to compare to, it seems that, while the amount of melt does seem more than average, we can only talk about it in the terms of the last 30 years and state we simply don't know what was seen before. For instance, we don't have any records to indicate the amount of melt that took place during the 1930s, a period that we do know was warmer than what we see now.

"Posted By: sullivanweather at 12:20 PM EDT on August 24, 2007. Nash28, what are you trying to say? That Greenland was named Greenland because it was green?"

"Posted By: BahaHurican at 9:15 PM GMT on August 24, 2007. Ayup"

Actually, no one really knows.

But the name does not matter, you could call it BooBooLand. ;-)

All you have to do is look at the archaeology to see how many times it was settled, froze out, settled, froze out, etc. and who did it.Each time they did it I'm pretty sure they didn't say "hey, there's a big chunk of ice, let's call it home" ;-)